78 S. WALTER RANSON 



number in the dorsal root would correspond closely to the num- 

 ber of modullated afferent fibers in the nerve just beyond the 

 ganglion. 



The ratio of cells to fibers varies with the animal and the 

 nerve stiuded, but in the second cervical nerve of the white rat 

 Ranson ('08) found a very constant ratio of 3.2 cells for each 

 meduUated afferent fiber in the dorsal root. This is explained 

 by the fact that the large cells which as already stated represent 

 about one-third of the total number are associated with medulla- 

 ted fibers, while the small cells (two-thirds of the total number) 

 are associated with non-medullated fibers. 



We wish now to present evidence to show that the axons of 

 the small cells are represented by the non-medullated fibers which 

 we have demonstrated in the peripheral nerves. 



6. Axonal reaction in the small cells of the spinal ganglion 

 following lesion of the associated nerve 



All who have investigated the subject, Fleming ('97), Cox 

 ('98), Koster ('03), Lugaro ('04), Warrington and Griffith ('04), 

 and Ranson ('09) agree that the vast majority (anywhere from 

 85 per cent to 100 per cent) of the cells in the spinal ganglion show 

 chromatolysis after division of the associated nerve. Koster 

 ('03) has maintained that since nearly all the cells react as if their 

 axon had been cut, the numerical results showing many more 

 cells than nerve fibers must be incorrect. But the counts of the 

 medullated fibers and ganglion cells have been too often confirmed to 

 be open to doubt; and we must explain the discrepancy between 

 the numerical and experimental results, not by denying the cor- 

 rectness of either, but by the fact that the non-medullated axons 

 of the small cells were not taken into consideration in the enu- 

 meration. 



Lugaro ('04), Cox ('98), and Ranson ('09) have shown that 

 the small cells show typical axonal reaction and react earlier and 

 more energetically than the large cells. Ranson ('09) has also 

 demonstrated that in the rat few of the large cells show irrepar- 

 able chromatolysis while the small cells degenerate and disappear 



